The present invention relates to a copying apparatus for developing an image on a photo-pressure sensitive sheet.
A conventional copying apparatus, such as a developing apparatus for a photograph, reader printer for a microfilm and so on, exposes a photo-sensitive paper to the light transmitted through or reflected from an original, and develops the exposed paper so that an image of the original is formed thereon. In this kind of apparatus, however, a unique chemical agent is used to develop the exposed paper so that the construction of the developing apparatus is complicated. Recently, the copy machine using a photo-pressure sensitive paper, such as U.S. Pat. Nos. 4,440,846 and 4,399,209 and Copending U.S. patent application Nos. 024,432 filed on Mar. 11, 1987 and 943,195 filed on Dec. 18,1986 have been proposed. To elaborate, it is provided with microcapsules which contain a chromogenic material and photo-sensitive composition etc., and are cured by light.
Upon completion of exposure, the photo-pressure sensitive paper is pressed by a press roller to rupture the microcapsules which are not cured. The chromogenic material and photo-sensitive composition etc., accordingly flows from the ruptured microcapsules and the chromogenic material reacts with a developing agent coated on either the photo-pressure sensitive paper or a transfer sheet where the image of the object will be formed. As a result, the construction of the copying apparatus can be simplified. The photo-pressure sensitive paper, however, must be handled with utmost care because the microcapsules may be ruptured by an outside force. In addition, if a cut sheet of a predetermined size is used, it is difficult to fit the sheet into the copying apparatus, and a feeding apparatus for the cut sheets is complicated. In order to solve the above problem, the inventor realized that the photo-pressure sensitive paper can form a roll. Accordingly, attachment to the apparatus can be simplified; and long continuous usage is possible once it is attached; the sheet can be fed simply by a roller and so on. However, there exists another problem as follows. When the copier is so constructed that an exposure magnification of the image on the recording paper is set at will, an exposure area and an exposure position of the image vary in response to the selected magnification of exposure. Since the conventional copy apparatus always feeds a sheet a predetermined length, it is impossible to expose the recording sheet from the edge thereof in all cases, resulting in wasteful use of paper.